DEGRADATION OF TRITIATED DIHYDROSPHINGOSINE IN INTACT RAT

Tritiated dihydrosphingosine, prepared by the catalytic reduction of sphingosine with tritium gas in the presence of platinum on charcoal, was administered by intravenous injection to mature rats. The animals were sacrificed after periods of time which varied from 15 to 90 min and the total lipids of the livers were isolated. Between 18 and 26% of the injected radioactivity were present in the liver lipids and were shown to be about equally divided between the long-chain base groups and the fatty acid groups. The largest part of the tritium of the fatty acid fraction was present in palmitic acid. Both the amount and the intramolecular distribution of the radioactivity in the palmitic acid led to the conclusion that this compound was formed directly from the injected dihydrosphingosine by reactions which resulted in the metabolic removal of carbon atoms 1 and 2 from the lipid base molecule. Evidence was obtained that sphingosine and phytosphingosine are probably not intermediates in the enzymatic degradation of dihydrosphingosine. © 1968, American Chemical Society. All rights reserved.